Currently, "Information superhighway" and "multimedia" are probably the most often spoken and least often understood aspects of a coming revolution in data communication. Although issues specific to an information superhighway are beyond the scope of the present discussion, interactive multimedia systems are very much within the present scope.
An interactive multimedia system is broadly defined as a system capable of processing, storing, communicating and coordinating data pertaining to visual information, aural information and other information. Visual information is generally divided into still picture or graphics and full motion video or animation categories. In the vernacular of those involved in multimedia, such visual information is generically referred to as "video." Aural information is generally divided into speech and non-speech categories and is generically referred to as "voice." "Other information" is directed primarily to computer data, often organized in files and records, and perhaps constituting textual and graphical data. Such computer data are generally referred to as "data."
To date, multimedia has, for the most part, been limited to stand-alone computer systems or computer systems linked together in a local area network ("LAN"). While such isolated systems have proven popular and entertaining, the true value of multimedia will become apparent only when multimedia-capable wide area networks ("WANs") and protocol systems are developed, standardized and installed that permit truly interactive multimedia. Such multimedia systems will allow long distance communication of useful quantities of coordinated voice, video and data, providing, in effect, a multimedia extension to the voice-only services of the ubiquitous telephone network.
Furthermore, as the volume of information communicated through the networks continued to expand, it became apparent that the single dial-up lines (either analog or digital) dedicated to transfer the information through the networks were inadequate. More specifically, the single dial-up lines could not transfer the information at a fast enough rate to keep up with the tremendous expansion. In connection therewith, the techniques to employ several independent dial-up circuits to increase the available transfer rate demonstrated many limitations. For instance, one of the more difficult problems was coordinating the information that traveled through the individual circuits so that the information could be reassembled at the receiving end in the proper sequence. This problem generally occurs because the independent circuits may be routed through intervening switched networks that traverse different paths through the entire network. Obviously, the delays through separate paths in the network are typically not identical thereby causing differing transit time delays for information streams carried on different circuits.
Attempts have been made in the past to manage the large volume of information through the network infrastructures. One such effort was developed by the Bandwidth ON Demand Interoperability Group ("BONDING"). The charter of the group is to develop common control and synchronization standards necessary to manage high speed information as it travels through networks such as the public network. The standards are embodied in Interoperability Requirements for Nx56/64 kbit/s Calls, Version 1.0, Bandwidth ON Demand Interoperability Group (1992), and, Interoperability Requirements for Nx56/64 kbit/s Calls, Version 1.1, Bandwidth ON Demand Interoperability Group (1992). The aforementioned standards are herein incorporated by reference. The standards allow equipment from separate vendors to interoperate over existing switched networks and integrated services digital networks. The standards describe four modes of inverse multiplexer ("I-MUX") interoperability. It allows I-MUXs from different manufacturers to subdivide a wideband signal into multiple 56- or 64-Kbps channels, pass these individual channels over a switched digital network, and recombine them into a single high-speed signal at the receiving end.
More specifically, the BONDING specification discloses a set of methods that allow the receiving endpoints to measure the delay or relative latency between multiple circuits or channels that are to be combined into a single virtual communications channel. The BONDING specification then provides for variable buffering for the individual channels so that the relative latencies between channels are reconciled. In one of the most prevalently employed modes of operation, the equipment compliant with the BONDING specification will determine the relative latencies at the inception of the communications session and assumes that the relationships do not change. In other modes of operation, contingencies provide for the real-time monitoring of the relative latencies and for a dynamic alteration of the number of individual channels making up the bonded channel. A relatively high level of overhead is associated with the other modes of operation and, to date, these modes have not been prevalently employed.
Accordingly, what is needed in the art is a recognition that relative latencies in communications networks may be quantified and, more specifically, a system and method whereby the relative latencies may be associated with a bonded call so that the bonded call can, then, be transferred, placed in a hold state and retrieved without requiring that the values of the relative latencies be relearned once established.